Peer to peer (P2P) implies a technology that shares digital resources together through a direct exchange without a server between different devices such as a computer, and the like. A P2P service includes a file exchange, chatting such as a messenger, and the like. Wireless P2P applies the P2P technology to a wireless terminal such as a cellular phone. In a wireless P2P environment, an on-demand data distributing technology is an essential element technology in a ubiquitous environment to come up.
FIG. 1 is a reference diagram for schematically describing a process of discovering peer that will bring required data by using a carrier sense multiple access/collision avoidance mechanism in a wireless peer to peer environment.
A mobile node (MN) requesting data transmits a signal for requesting the corresponding data to the vicinity thereof Then, terminals which are positioned within a transmission range of the mobile node MN receive the signal and terminals N1 to N5 having the corresponding data send response signals, respectively. The mobile node MN selects a terminal sending a response signal that arrives first and receives data from the terminal The mechanism is a contention-based medium access controlling mechanism.
Meanwhile, the use of multimedia data such as a digital image, a moving picture, and the like is increased even in a wired environment and a wireless environment and an interchange need is also increased due to improvement in performance of a wireless terminal such as a cellular phone. In the case of the multimedia data, a quality of service (QoS) should be ensured and pseudo streaming that verifies or reproduces data while downloading should be supported.